Disposition of transponder coupling elements in tires

ABSTRACT

A pneunatic radial ply tire ( 500, 600, 900, 1000, 1100, 1200, 1300, 1400 ) having a tread ( 538, 638, 938, 1038, 1138, 1238, 1338, 1438 ), a carcass structure ( 560, 660, 960, 1060, 1160, 1260, 1360, 1460 ) and a belt structure ( 546, 646, 946, 1046, 1146, 1246, 1346, 1446 ) has an electrically conductive and electrically continuous single-turn hoop ( 510, 610, 910, 1010, 1110, 1410 ) disposed about the circumference of the tire. The hoop might be provided as a coupling element in a transponder and interrogator system and in some designs as a structural element of the tire.

TECHNICAL FIELD

This invention relates to a pneumatic tire incorporating an integratedcircuit transponder for use in tire identification and for thetransmission of such tire data as temperature and pressure and the like.More particularly, the invention relates to the combination of atransponder and an electromagnetic coupling element and to thedisposition of both within a tire.

BACKGROUND OF THE INVENTION

For a century, the Goodyear Tire & Rubber Company of Akron Ohio,assignee of the present invention, has been the uncontested industryleader in tire product technology.

For example, as early as 1892, a puncture-resistant tire was patented.In 1934, a year recognized as the beginning of the runflat era, Goodyearintroduced the Lifeguard (tm) safety tube, a fabric tube within thetire, used commercially by auto makers and on trucks. In 1993,Goodyear's Eagle GS-C EMT (Extended Mobility Technology) won theDiscover Award for Automotive Technological Innovation. In 1996, theGoodyear Eagle F1 runflat tire was chosen as standard equipment on the1997 Chevrolet C-5 Corvette.

Other examples of the strides Goodyear has taken in the advancement oftire and related technologies include, but are not limited to, thefollowing patented inventions:

Commonly-owned U.S. Pat. No. 3,665,387 (Enabnit; 1972), entitledSIGNALLING SYSTEM FOR LOW TIRE CONDITION ON A VEHICLE, incorporated inits entirety by reference herein, discloses a low tire pressure warningsystem adaptable for any number of wheels of a vehicle and providingdashboard indications of system operation and low pressure conditionswhile the vehicle is in motion.

Commonly-owned U.S. Pat. No. 3,831,161 (Enabnit; 1974), entitledFAIL-SAFE MONITORING APPARATUS, incorporated in its entirety byreference herein, discloses monitoring vehicle tire pressure wherein theoperator is warned of an abnormal or unsafe condition of one or more ofthe tires.

Commonly-owned U.S. Pat. No. 3,872,424 (Enabnit; 1975), entitledAPPARATUS AND METHOD FOR TRANSMITTING AUXILIARY SIGNALS ON EXISTINGVEHICLE WIRING, incorporated in its entirety by reference herein,discloses communicating with low tire pressure monitoring circuits usingpower pulses carried on existing vehicle wiring (e.g., the turn signalcircuits).

Commonly-owned U.S. Pat. No. 4,052,696 (Enabnit; 1977), entitled TIRECONDITION MONITOR, incorporated in its entirety by reference herein,discloses a tire condition sensing circuit that includes a ferriteelement that changes from a ferromagnetic to a non-ferromagnetic statein response to a temperature increase above the material's Curie point.

Commonly-owned U.S. Pat. No. 4,099,157 (Enabnit; 1978), entitled SINGLEWIRE POWER/SIGNAL SYSTEM FOR VEHICLE AUXILIARY DEVICES, incorporated inits entirety by reference herein, discloses providing both power to andreceiving detection signals from a remotely located condition monitoringdevice using a single wire with ground return through the vehicle frame.

Commonly-owned U.S. Pat. No. 4,108,701 (Stanley; 1978), entitled METHODFOR MAKING HOSE INCORPORATING AN EMBEDDED STATIC GROUND CONDUCTOR, andrelated U.S. Pat. No. 4,168,198 (Stanley; 1979), entitled APPARATUS FORMAKING HOSE INCORPORATING AN EMBEDDED STATIC GROUND CONDUCTOR, bothincorporated in their entirety by reference herein.

Commonly-owned U.S. Pat. No. 4,911,217 (Dunn, et. al.; 1990), entitledINTEGRATED CIRCUIT TRANSPONDER IN A PNEUMATIC TIRE FOR TIREIDENTIFICATION, incorporated in its entirety by reference herein,discloses an RF transponder in a pneumatic tire. FIG. 1a of this patentillustrates a prior-art identification system (“reader”) that can beused both to interrogate and provide energy to the transponder insidethe tire. The identification system includes a portable hand-held modulehaving within it an exciter and associated circuitry for indicating to auser the numerical identification of the tire/transponder in response toan interrogation signal.

Commonly-owned U.S. Pat. No. 5,181,975 (Pollack, et. al.; 1993),entitled INTEGRATED CIRCUIT TRANSPONDER WITH COIL ANTENNA IN A PNEUMATICTIRE FOR USE IN TIRE IDENTIFICATION, incorporated in its entirety byreference herein, discloses a pneumatic tire having an integratedcircuit (IC) transponder and pressure transducer. As described in thispatent, in a tire that has already been manufactured, the transpondermay be attached to an inner surface of the tire by means of a tire patchor other similar material or device.

Commonly-owned U.S. Pat. No. 5,218,861 (Brown, et al.; 1993), entitledPNEUMATIC TIRE HAVING AN INTEGRATED CIRCUIT TRANSPONDER AND PRESSURETRANSDUCER, incorporated in its entirety by reference herein, disclosesa pneumatic tire having an integrated circuit (IC) transponder andpressure transducer mounted within the pneumatic tire. Uponinterrogation (polling) by an external RF signal provided by a “reader”,the transponder transmits tire identification and tire pressure data indigitally-coded form. The transponder is “passive” in that it is notself-powered, but obtains its operating power from theexternally-provided RF signal.

The commonly-owned U.S. Patents referenced immediately hereinabove areindicative of the long-standing, far-reaching and ongoing efforts beingmade by the Goodyear Tire & Rubber Company in advancing tire producttechnology. In particular, the lattermost patent, U.S. Pat. No.5,218,861 ('861), describes “a pneumatic truck tire having an integratedcircuit transponder including an antenna coil which functions as asecondary winding coupled to the annular tensile member formed fromsteel wire and acting as a primary winding in the manner describedabove.” The “annular tensile member” referred to is specifically one ofthe tire's two spaced-apart beads which is, in effect, used as theprimary winding of a transformer whose secondary winding is the antennacoil of the transponder installed within the tire. U.S. Pat. No.4,911,217, is referenced in the '861 patent as utilizing this same sortof electric-field coupling (col. 5, 1. 10+).

The '861 patent describes difficulties of incorporating the large-loopantennas of transponders into the tire manufacturing process wherein thetire must undergo a “blow up” from a cylindrical shape into the familiartoroidal shape of tires. The use of a small planar loop antenna, as thesecondary winding of a transformer and one of the tire beads as theprimary winding, enables the interrogation of a tire-mounted transponderfrom any position about the bead. Unfortunately, while the bead thusused enables easy communication between the transponder and theinterrogator device when the tire is unmounted upon a metal wheel—theuse of the bead as the primary winding is adversely influenced by theclose proximity of the bead to the wheel when the tire is in use. Inother words, the use of the tire bead as the primary winding in amagnetically coupled transponder system presents difficulties associatedwith the close proximity between the tire bead and the closely adjacentmetallic wheel which presents the potential for interference with the RFcommunication between the transponder and the external interrogatorwhich activates the transponder.

SUMMARY OF THE INVENTION

The present invention relates to a pneumatic radial ply runflat tirehaving a tread, a carcass comprising a radial ply structure having twoor more plies, a belt structure comprising two or more belts locatedbetween the tread and the radial ply structure, an innerliner and twosidewalls each reinforced by one or more wedge inserts, and anelectrically conductive and electrically continuous, single-turn hoopdisposed radially inward of the tread and belt structure and radiallyoutward of the carcass structure. The function of the hoop is that of acoupling element in a transformer comprising the hoop as the primarywinding and the coil of a tire-mounted transponder as the secondarywinding such that the tire-mounted transponder would have 360-degreereadability about the circumference of the tire by a transponderinterrogator that is external to the tire. The electrically continuoussingle-turn hoop has an electrical resistance about its circumference ofpreferably less than 10 ohms and is constructed of material resistant tofatigue and corrosion in the environment of an interior of a pneumatictire. The electrically continuous single-turn hoop is more or lessrectangular in cross section and is made from a solid band ofelectrically conductive material. Or the hoop can be made from amultiplicity of strands of electrically conductive material suitable toresist fatigue failure or of a single strand or wire of electricallyconductive material that is non-rectangular in cross section. The planeof the hoop could contain the equatorial plane of the tire or it couldlie on either side of the equatorial plane of the tire. The hoop couldbe disposed between any two of the two or more belts of the beltstructure or radially outward of the belt structure and radially inwardof the tread. Such a coupling element hoop is intended also to be usedin conjunction with a tire-mounted transponder within a tire that is notdesigned for runflat operation.

The transponder coupling-element hoop of the present invention isintended for use in tires having a belt structure having two laterallyspaced apart sides that are disposed more or less symmetrically withrespect to each other about the equatorial plane of the tire. Morespecifically, the electrically conductive and electrically continuoussingle-turn hoop would be disposed radially inward of the tread andbetween the two laterally spaced apart portions of the belt structure.The hoop would have the above described properties of cross-sectionalshape and solid or stranded structure and an electrical resistance aboutthe circumference of the tire of preferably less than 10 ohms.

The invention contemplates yet further the use of a tread-supportingstructural hoop in the role of a primary winding in a coupling-elementtransformer allowing 360-degree readability of a tire-mountedtransponder. Such a structural hoop would have the above describedelectrical properties of a single-turn, electrically continuous loophaving an electrical resistance of preferably less than 10 ohms aboutthe circumference of the tire.

Other benefits and advantages of the invention will become apparent tothose skilled in the art to which it pertains upon a reading andunderstanding of the following detailed specification.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made in detail to preferred embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. The drawings are intended to be illustrative, and not to belimiting. Although the invention will be described in the context ofthese preferred embodiments, it should be understood that the specificembodiments are not intended to limit the spirit and scope of theinvention to these particular embodiments.

Certain elements in selected ones of the drawings may be illustratednot-to-scale, for illustrative clarity.

Often, similar elements throughout the drawings may be referred to bysimilar references numerals or even by the same reference numeral. Forexample, the element 199 in a figure (or embodiment) may be similar inmany respects to the element 299 in an other figure (or embodiment).Such a relationship, if any, between similar elements in differentfigures or embodiments will become apparent throughout thespecification, including, if applicable, in the claims and abstract.

In some cases, similar elements may be referred to with similar numbersin a single drawing. For example, a plurality of elements 199 may bereferred to as 199 a, 199 b, 199 c, etc.

The cross-sectional views, if any, presented herein may be in the formof “slices”, or “near-sighted” cross-sectional views, omitting certainbackground lines which would otherwise be visible in a truecross-sectional view, for illustrative clarity.

The structure, operation, and advantages of the preferred embodiments ofthe invention will become further apparent upon consideration of thefollowing description taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1A is a schematic side view of a tire containing a prior arttransponder;

FIG. 1B is a cross-sectional view of the tire through line 1B—1B of FIG.1A;

FIG. 1C is a second cross-sectional view through line 2C—2C of the tireof FIG. 1A, where the tire has been rotated 180;

FIG. 2A is a schematic side view of a tire containing a transponder anda generalized hoop/loop;

FIG. 2B is a cross-sectional view through line 2B—2B of the tire of FIG.2A;

FIG. 2C is a second cross-sectional view through line 2C—2C of the tireof FIG. 2A, where the tire has been rotated 180;

FIG. 3 is a oblique view of an generalized prior art transponder andcoil;

FIG. 4 is a plan view of the transponder of FIG. 3 shown in relation toa tire bead;

FIG. 5 is a meridional cross-sectional view of a runflat tire having atread-supporting structural hoop;

FIG. 6 is a close-up view of the central portion of the FIG. 5, showinga transponder embedded radially outward of the structural support hoop;

FIG. 7A is an oblique view of a prior art patch-type transponder shownmounted on the inside wall of a tire;

FIG. 7B is a cross-sectional view of the transponder of FIG. 7A;

FIG. 8A is an oblique view of a generalized patch-type transponder;

FIG. 8B is a cross-sectional view of the generalized patch-typetransponder of FIG. 8A;

FIG. 9 is a meridional cross-sectional view of a runflat tire having atread-supporting structural hoop and a patch-type transponder disposednear the hoop;

FIG. 10 is a meridional cross-sectional view of a runflat tire with anon-structural hoop/loop disposed between the carcass structure and thebelt structure;

FIG. 11A is a close-up view of the central portion of FIG. 10, showing apatch-type transponder mounted inside the tire;

FIG. 11B is a close-up view of the central portion of a tireincorporating a hoop/loop and an embedded transponder disposed radiallyinward of the hoop/loop;

FIG. 11C is a close-up view of the central portion of a tireincorporating a hoop/loop and an embedded transponder disposed radiallyoutward of the hoop/loop;

FIG. 11D is a close-up view of the central portion of a tireincorporating a hoop/loop disposed between the belts of the beltstructure;

FIG. 12 is a close-up cross-sectional view of a patch-mountedtransponder and a cable-type hoop/loop disposed between the carcassstructure and the belt structure;

FIG. 13 is a close-up cross-sectional view of a hoop/loop disposedbetween the two halves of a split-belt tire; and

FIG. 14 is a meridional cross-sectional view of a runflat tireincorporating an electrically conductive loop/hoop between the carcassstructure and the belt structure.

DEFINITIONS

“Apex” means an elastomeric filler located radially above the bead coreand between the plies and the turnup plies.

“Axial” and “axially” means the lines or directions that are parallel tothe axis of rotation of the tire.

“Bead” or “bead core” generally means that part of the tire comprisingan annular tensile member of radially inner beads that are associatedwith holding the tire to the rim; the beads being wrapped by ply cordsand shaped, with or without other reinforcement elements such asflippers, chippers, apexes or fillers, toe guards and chaffers.

“Belt structure” means at least two annular layers or plies of parallelcords, woven or unwoven, underlying the tread, unanchored to the bead,and having both left and right cord angles in the range from 18 to 30relative to the equatorial plane of the tire.

“Breaker” is a word more generic than belt and includes unanchored pliesunderlying the tread having cord angles with respect to the equatorialplane forming angles, either left or right, up to 90 degrees withrespect to the equatorial plane of the tire.

“Carcass” means the tire structure apart from the belt or breakerstructure, tread, undertread, and sidewall rubber over the plies, butincluding the beads.

“Circumferential” most often means circular lines or directionsextending along the perimeter of the surface of the annular treadperpendicular to the axial direction; it can also refer to the directionof the sets of adjacent circular curves whose radii define the axialcurvature of the tread, as viewed in cross section.

“Cord” means one of the reinforcement strands of which the plies in thetire are comprised.

“Cord Angle” means the acute angle, left or right in a plan view of thetire, formed by a cord with respect to the equatorial plane;

“Equatorial plane” means the plane perpendicular to the tire's axis ofrotation and passing through the center of its tread; or the planecontaining the circumferential centerline of the tread.

“Inner” means toward the inside of the tire and “outer” means toward itsexterior;

“Innerliner” means the layer or layers of elastomer or other materialthat form the inside surface of a tubeless tire and that contain theinflating fluid within the tire.

“Insert” means the same as “wedge insert,” which is the crescent- orwedge-shaped reinforcement typically used to reinforce the sidewalls ofrunflat-type tires; it also refers to the elastomericnon-crescent-shaped insert that underlies the tread.

“Interrogator” refers to a device that interrogates a transponder and,in the case of a passive transponder, provides electrical energy to thetransponder so that the latter can transmit energy to the interrogator,the antenna of which might be mounted near the wheel of each tire on avehicle, or it might be hand-held by a technician who is examining aspecific tire that is either mounted on a vehicle or not mounted on avehicle.

“Lateral” means a direction parallel to the axial direction.

“Meridional” refers to the meridian direction of a tire as, for example,a meridional cross-sectional view in which the plane of the crosssection contains the tire's axis.

“Normal inflation pressure” means the specific design inflation pressureat a specified load assigned by the appropriate standards organizationfor the service condition for the tire.

“Normal load” means the specific design inflation pressure and loadassigned by the appropriate standards organization for the servicecondition for the tire.

“Ply” means the same as “carcass ply,” which is a cord-reinforced layerof rubber-coated meridionally deployed or otherwise parallel cords.

“Radial” and “radially” mean directions radially toward or away from theaxis of rotation of the tire.

“Radial ply structure” means the one or more carcass plies or which atleast one ply has reinforcing cords oriented at an angle of between 65and 90 with respect to the equatorial plane of the tire.

“Radial ply tire” means a belted or circumferentially-restrictedpneumatic tire in which at least one ply has cords which extend frombead to bead are laid at cord angles between 65 and 90 with respect tothe equatorial plane of the tire.

“Runflat” or “runflat tire” is a pneumatic tire that is designed toprovide limited service while uninflated or underinflated.

“Shoulder” means the upper portion of sidewall just below the treadedge.

“Sidewall” means that portion of a tire between the tread and the bead.

“Wedge insert” means the same as “insert,” which is the sidewallreinforcement used in runflat tires.

DETAILED DESCRIPTION OF THE INVENTION

An antenna is an essential feature of a radio frequency (RF)transponder. There are two main configurations and locations for theantenna of a tire transponder: (i) a “coil” antenna is typically locatedwith the transponder in a single, self-contained communicating packageof transponder hardware; and (ii) a “loop” antenna, which extends fromthe transponder about the circumference of the tire.

Given the tire-manufacturing challenges presented by installing alengthy loop antenna system that extends about the circumference of thetire, a transponder having a coil-type antenna is preferred. Suchtransponders can be quite small, allowing them to be imbedded within atire during manufacturing of the tire, or such transponders, measuringon the order of the size and shape of a half-dollar coin, might bebonded as a “patch” to the inside of a tire after the tire is sold oreven after the tire has seen extended service.

The present invention relates to the first type of transponder describedabove, the one having a small coil antenna. However, due to specificproblems relating to interrogator/transponder communication as describedin more detail below, the coil-type transponder antenna can be made tocommunicate more efficiently with an interrogator antenna locatedexternal to the tire if the transponder's coil antenna is used inconjunction with a large, continuous, electrically conductive loop.

FIGS. 1A, 1B and 1C illustrate three views of a prior art tire-installedcoil-type RF transponder system 100 comprising a passive transponder 102disposed within a pneumatic tire 104. The passive transponder 102 ismounted in any suitable manner to an inner surface 106 of the tire, suchas using the techniques described herein below and in the any of thepatents and patent applications cited herein. An interrogator antenna108 is disposed on the vehicle, adjacent the tire 104, such as in awheel well of the vehicle directly next to the tire. The interrogatorantenna 108 provides electromagnetic radiation for powering thetransponder 102 and receives data-carrying signals from the transponder.

As illustrated in FIGS. 1A1B and 1C the interrogator antenna 108 isdisposed at the “12 O'clock” orientation with respect to the tire 104,i.e., near the top portion of the vehicle-mounted tire. It should beunderstood that the interrogator antenna 108 may be disposed at anyposition suitable for RF coupling with the transponder 102 withoutinterfering with movement (rotation, steering, rebounding) of the tire104.

The present invention is directed to providing “360-degree readability”,which means that the antenna of the interrogator will be able tocommunicate, from any location about the tire's circumference, with atire-mounted transponder disposed at any location within the tire, sothat a person using a hand-held interrogator would not have to move theantenna around the circumference of the tire in order to communicatewith, a tire-mounted transponder. With 360-degree readability, theantenna of the interrogator can be positioned anywhere near the tire'scircumference in order to interact with the transponder. In the case ofchassis-mounted or on-board antenna systems, as might be used in thecontinuous monitoring of tire pressure, temperature and other variablesof all of the tires on a given vehicle, a preferred location for theantenna of the interrogator is near the top of the tire, preferablyabove the tire's axis of rotation. This is especially so in the case offront wheels which, when the vehicle is cornering, the frontmost andrearmost portions of each steering tire move laterally, which wouldaffect communication between the interrogator antenna and thetransponder if the antenna were disposed in the forward or rearwardportions of the vehicle's wheel wells. Thus the over-the-tire locationfor a vehicle-mounted interrogator antenna is more or less directlyabove the tire's axis of rotation, allowing the antenna to beequidistant from the tire at all times.

FIGS. 2A,2B and 2C illustrate a generalized tire-mounted RF transpondersystem 200 (compare 100) comprising a passive transponder 202 (compare102) disposed within a pneumatic tire 204 (compare 104). Thetire-mounted transponder system 200 is similar to the above-describedtransponder system 100 in the following respects. A transponder 202 ismounted in any suitable manner to an inner surface 206 of the tire. Aninterrogator antenna 208 (compare 108) is disposed on the-vehicle,adjacent the tire 204, such as in a wheel well of the vehicle directlynext to and preferably near the top of the tire 204. The antenna 208provides RF electromagnetic radiation to the transponder 202, both forpowering the transponder and receiving data-carrying signals from it.

This generalized illustration of the tire-mounted transponder system 200includes an electrically conductive hoop 210 extending circumferentiallyaround the inner surface 206 of the tire 204. The hoop 210 isillustrated as being slightly offset from an axial centerline(equatorial plane) of the tire 204, though this is not necessary to thefunction of the hoop in relation to the transponder. The hoop 210 is anelectrically-conductive member having the function of a primary windingof a coupling transformer of which a coil antenna of the transponderfunctions as a secondary winding of the functional coupling transformer.Generally, the hoop 210 enhances coupling between the transponder 202and the external interrogator antenna 208 and can thus be considered asa “coupling element.” The hoop 210 is suitably a single turn ofelectrically conductive material having its ends connected (shorted, orsimply electrically continuous) to one another, but it may comprisemultiple turns or layers of wire or conductive material which behaves asa single electrically conductive loop. The hoop 210 should have a lowelectrical resistance, preferably less than 10 ohms.

As illustrated in FIGS. 2A,2B and 2C, the vehicle-mounted antenna 208 isdisposed at the “12 O'clock” orientation with respect to the tire 204,such as abreast of a top portion of the tire. It should be understoodthat the interrogator antenna 208 may be disposed at any positionsuitable for RF coupling with the transponder 202 without interferingwith movement (rotation, steering, rebounding) of the tire.

Regarding the location of an actual or practical hoop 210, it should beunderstood that the hoop is shown extending circumferentially around theinner surface 206 of the tire 204, slightly offset from the equatorialplane EP of the tire, for illustrative purposes only. It is within thescope of the invention that the hoop 210 may be disposed on theequatorial plane of the tire 204, passing directly underneath, orradially outward of, the transponder 202, and may also be “buried” orembedded in the body of the tire 204. Or the hoop 210 can be locatedoutside of the equatorial plane of the tire. Regarding the hoop 210itself, it should be understood that the hoop is an exemplary complete,endless, short-circuit loop of any electrically-conductive materialsuitable to function as the above described transformer couplingelement. The hoop 210 is suitably constructed of material such as, forexample, brass-plated high-tensile strength steel, that exhibits goodmechanical strength and resistance to corrosion and fatigue in theenvironment of an interior of a pneumatic tire. For example, the hoop210 may comprise multiple strands of such wire, which optionally may beplated (e.g., with nickel or gold).

It is within the scope of the invention that the hoop 210 may be formedas two or more lengths of wire joined in any suitable manner (such as bywrapping, welding or soldering) at their ends to form a continuous hoopextending around the entire circumference of the tire 204.

In summary, the present invention relates to the use of coil-typetransponder systems, in which the transponder's coil antenna is part ofa transformer in which the transponder's coil antenna (which may have aferrite or other magnetic material as a core) operates as the secondarywinding through which the transponder can receive energy from andcommunicate with a transponder interrogator device located external tothe tire. The primary winding of such a transformer is a large-diameterelectrically conductive and continuous loop mounted within a tire.

Use of Tire Bead as a Primary Winding Hoop Coil

One of the two spaced-apart metallic beads of a tire can satisfy theabove described requirements of a large-diameter transformer primarywinding mounted within a tire. In fact, the use of one of the tire beadsas the primary winding of an interrogator/transponder system isdescribed in the above referenced and commonly held U.S. Pat. Nos.5,181,975 and 5,218,861.

However, the disadvantage in using one of the tire's two beads as theprimary winding of the transformer linking the transponder to theinterrogator is the electromagnetic influence associated with theelectrically conductive metallic wheel upon which the tire is mountedand to which the bead is closely adjacent. Accordingly, the presentinvention addresses the installation and use of a continuous hoop orloop, electrically conductive tire element disposed far from the beads,as preferably in or close to the tread region of the tire. Such a hoopmight or might not serve structural functions within a tire in additionto performing the function of a primary transformer winding. Forexample, an electrically conductive hoop of metal might be installed inthe region of the tread, from which location the loop or hoop can servethe function of being an electromagnetic linking element in thetransponder/interrogator system. That is, such a loop or hoop might beinstalled in a new tire for the specific purpose of being the primarywinding of the transformer. Or the hoop might be installed in a tire asa structural element, e.g., as a tread reinforcing structure of the sortdescribed further below as well as in European Patent Application99100920.0, having a common assignee with the present invention andincorporated by reference herein and which is described in detail, withdiagrams, below. Such structural hoops or loops, when performing theadditional function of being a transformer primary winding in atransponder system, allow a transponder to be disposed in a specificplace within a tire, (as near the tread region) while maintaining theinterrogator communication with the transponder from any location aboutthe tire's major circumference, even from the opposite side of the tirefrom the interrogator. For example, an interrogator would be able tocommunicate with a tire-mounted transponder whose location within thetire might be on the far side of the large diameter of a tire from thelocation of the antenna of an interrogator device.

Thus, the present invention provides a tire with a continuous circularloop or hoop that can act as the primary winding of atransponder-linking transformer, regardless of whether a transponder isinstalled in the tire during manufacture of the tire or as anafter-market add-on. In the latter instance, a tire-status transpondermight be installed within a newly installed tire or within a used tirefor the purpose of measuring, monitoring and transmitting tire pressureand/or temperature data, or other variables such as, tire mileage ortire rotational speed. The installation of hoop within the tire duringits manufacture would thus provide the primary winding of theaforementioned transformer, whether or not a transponder is alsoinstalled during manufacture of the tire or is installed aftermanufacture of the tire or is never installed at all.

The present invention can also provide for a primary transformer loopwithin a region of the tire that is far removed from an electricallyconductive metallic wheel assembly, the loop being used in conjunctionwith a tire-status and/or tire-identification transponder that is alsoinstalled within a tire during the tire manufacturing process. Exampleswill be given and discussed below.

The present invention can also employ the electrically conductivestructural elements such as the metallic tread-reinforcing beaddescribed in TIRE WITH IMPROVED RUNFLAT DESIGN, filed Jan. 20, 1999 asEuropean Patent Application 99100920.0, as the primary winding couplingelement described above.

Hoops and Loops

The phrases “loop or hoop” and “hoop/loop” as used herein are intendedto refer to an electrically conductive, single-turn loop or hoopdisposed more or less radially inward of the tread of a tire. It isintended that, unless otherwise stated or obviously implied, the phrases“loop or hoop” and “hoop/loop” be synonymous with the words “loop” and“hoop,” which would themselves also be mutually synonymous in thecontext of this disclosure unless otherwise stated (as in instanceswhere the transponder's coil-type antenna might be referred to as a“loop”). It is acknowledged that the term “hoop” implies or suggests astructure having greater structural rigidity than is implied orsuggested by the term “loop”. Within this disclosure, the words “hoop”and “loop” and variations of the phrase “hoop or loop” all refer toelectrically conductive tire components disposed more or less radiallyinward of a tire's tread region. The hoop/loop might have a structuralfunction within the tire as well as providing the aforementionedtransformer primary-winding, coupling element function that is requiredso that the interrogator external to the tire can achieve 360-degreereadability of the transponder within the tire. Or the hoop/loop mightbe installed within the tire for the sole non-structural purpose ofproviding the primary-winding transformer function mentioned above anddiscussed more fully below. In the post-production or after-marketinstallation of a tire-status monitoring transponder within a tire, thetransponder might be attached as a patch that is bonded by adhesiveand/or heat to the inside of a pneumatic tire designed for use on trucksor passenger vehicles. Such an aftermarket-installed transponder wouldbe able to interact electromagnetically with the hoop/loop installedwithin the tire during manufacture, provided the transponder's antenna,secondary loop or coil winding is appropriately aligned with theelectric and magnetic field lines associated with the large-diameterhoop/loop that functions as the primary winding of theelectromagnetically linking transformer.

An electrically conductive and continuous loop/hoop installed within atire during its manufacturing phase would allow a transponder to also beinstalled during tire production, in which case the transponder wouldhave the potential to be used in tire identification even during themanufacturing process, which would allow for tracking of individualtires during production), or and afterward, as stated, after the tire issold or has been in use.

Referring to FIG. 3, there is shown in oblique view a prior artintegrated circuit RF transponder system 300, as disclosed in the '861patent, having a transponder 320 and substantially planar antenna coilor antenna coil 322. The transponder 320 includes an integrated circuit324 mounted on a circuit board 326. The circuit board 326 is adhered tothe antenna coil 322 with a suitable epoxy or other adhesive compatiblewith the polyester insulation provided on the wires 308 forming theantenna coil 322. FIG. 4 is a view of a transponder system 400, asdisclosed in the '861 patent, (compare 300) from a directionperpendicular to the plane of the transponder's antenna coil 422 mountedon ply 430 of a tire near the bead wires 432. The long lower side of theoblong or elongated antenna coil 420 is positioned near (adjacent) thebead wires 432, which are partially shown. The lines 434 represent thereinforcing cords of the ply 430. The lines of X's depict the magneticfield lines uniformly distributed along the circumference of the beadwires 432 when alternating electrical current is induced in the bead byan interrogator mounted external to the tire. The bead wires 432correspond, in their electromagnetic role, to the hoop 210 in FIGS.2A,2B and 2C. The magnetic field lines vary in intensity in anexponentially decreasing manner as a function of radial distance fromthe bead wires 432. The bead wires 432, in other words, act as theabove-described primary winding of a transformer, coupling the magneticfield to the coil antenna secondary winding 420 in the transpondersystem 400.

A printed circuit board 426 has openings or holes 428 through whichelastomer may flow to increase the adhesion of the transponder 440(compare 340) to the other tire components. The holes 428 can have aconductive plating material for use as programming and test pads duringtransponder manufacture. A capacitor 438 is provided for electricalconnection in parallel with the coil winding, the leads (not shown) ofwhich are connected to electrodes of the transponder system 400 and itsintegrated circuit 424 substantially in the manner of the antennasillustrated and described in the U.S. Pat. No. 4,911,217 patent of Dunnet al. The numeral 436 denotes a space or location in or on the circuitboard 442 that receives a pneumatic pressure transducer.

Note that the annular tensile member or bead 432, has a curvature. Theantenna coil 422 need not precisely follow this curvature in order toachieve adequate electromagnetic coupling as disclosed in the '861patent of Brown et al.

Non-Structural Hoops and Loops

Referring now to FIGS. 2A,2B and 2C, there is shown a hoop 210 disposedwithin a tire 204. The sole purpose of the hoop 210 is to perform therole of being the primary winding of the transformer system describedabove. Such a hoop/loop 210 need not have a structural role in the tire.That is, if a non-structural loop or hoop of electrically conductivematerial, as shown in those FIGS. 2A,2B and 2C, could be easily andreliably secured within a tire, perhaps by being bonded to theinnerliner with an adhesive tape, then one low-cost solution would be toavailable to installing such hoops within tires either during the tiremanufacturing process or subsequent to it. However, due to the cyclicalflexural requirements of a tire, and to the temperature extremes towhich tires are exposed, the use of tape to bond such a loop 290securely inside a tire is not preferred.

A more practical and preferred way to reliably incorporate anon-structural, electrically conductive loop within a tire would be todispose it within the belt structure or between the belt structure andthe carcass structure.

Structural Hoops as Primary Windings

FIG. 5 shows in meridional cross-section, a runflat tire 500 accordingto the present invention having a tread 538 incorporating atread-reinforcing bead, or hoop 510, comprising a bundle of metal cordsor wires 540 embedded within an elastomeric support 542 disposed betweenthe carcass ply structure 544 and the belt structure 546 in theequatorial plane EP. In this example, the hoop 510 serves as astructural hoop whose structural function related to the runflatstructure and capabilities of the tire 500. Specifically, the bead orhoop 510 inhibits tread lift during runflat operation, and its rigidityprovides additional load-carrying capacity to the uninflated tire.

FIG. 6 is a close-up cross-sectional view of the central portion 600 ofthe tire 500 shown in FIG. 5, with a transponder 602 disposed radiallyoutward of the hoop 610 (compare 510). The axis of the coil 648 of thetransponder 602 is more or less parallel to, or has a parallel componentto the axis (not shown) of the hoop 610. In this example, thetread-reinforcing structural hoop 610 is electrically conductive andelectrically continuous in a single electrical loop about thecircumference of the tire and has an electrical resistance of preferablyless than 10 ohms. Such a structural hoop 610 can perform the role of aprimary transformer winding in relation to the secondary winding that isthe transponder coil 648 (which as illustrated has an axis parallel tothat of tire 500 and is wound about a ferrite core), in addition to itsrunflat tire-reinforcing structural function. Those skilled in the artwill recognize that the transponder 602 in this embodiment would have tobe installed during manufacture of the tire. However, as will bediscussed below, the structural element 510,610 shown in FIGS. 5 and 6,respectively, could also accommodate a transponder “patch” such as mightbe installed either during manufacture of the tire or after the tire issold, as perhaps during retreading. Transponder patches are discussedbelow.

The specific location of the transponder 602 shown in FIG. 6 (i.e.radially outward of the structural hoop 610) would serve well for atransponder whose main information-related functions might be thetransmission of tire identification data or data related to tiretemperature or tire rotational speed or total mileage. However, thetransponder location as shown would not necessarily be useful for themonitoring of tire pressure. However, were the transponder 602 to bedisposed radially inward of the hoop 610, a small hole of the sortdescribed in U.S. Pat. No. 5,500,065, to Koch et al., might be providedto allow communication of pressure information between the transponderand the inside of the tire. Disposition of the transponder 602 radiallyinward of the hoop 610 would not obviate the use of the hoop as aprimary winding in the transformer through which the transponder couldachieve electromagnetic communication with an interrogator deviceexternal to the tire, so long as the axis of the core of the transpondercoil 648 is more or less parallel to the axis (unshown) of the hoop 610,which would be more or less coincident with the axis of the tire.

“Patch” Transponders

U.S. Pat. No. 5,500,065, to Koch et al. and entitled, “Method forEmbedding a Monitoring Device with a Tire During Manufacture,” describesseveral strategies by which to install a transponder during the tiremanufacturing process. The Koch patent includes a patch-like transponderwhose appearance suggests that it could as well be installed subsequentto the tire manufacturing process.

FIG. 7A is an oblique view of a prior art patch type transponder package700 having a cover 750 secured to the inner wall 706 of a tire. Thecover 750 has an adhering surface which secures a monitoring transponder(not shown) to the tire's inner wall 706 such as, specifically, theinnerliner. Such a cover 750 can be made of rubber or other materialsand can be secured by vulcanization, including chemical cure, or securedby adhesive and/or heat to the inner surface of a tire. A slit-typeopening 752 communicates between the inside of the tire and thetransponder (not shown) beneath the cover 750. FIG. 7B is across-sectional view of a transponder 702 disposed between the patchcover 750 and the innerliner 706.

FIG. 8A is an oblique view of a generalized after-market patch cover 800with an opening 852 beneath which is a transponder (not shown). FIG. 8Bis a generalized cross-sectional view of the patch-on transponderpackage 801 with its patch cover 850 shown covering a generalizedpassive transponder 802 (compare 602), including its coil antenna (notshown), affixed to the innerliner 806 of a tire. The cover 850 containsa hole 852, which might be round or oblong or rectangular, communicatingbetween the transponder 820 and the inside of the tire.

The generalized “patch” type transponder 801 shown in FIGS. 8A and 8B isintended to represent, for the purposes of this disclosure, atransponder mounting arrangement that can be permanently attached to atire's innerliner either during manufacture of the tire or anytimesubsequent to manufacture of the tire. Such a generalized patchtransponder 801 will be shown in subsequent figures in this disclosure.It is not intended to represent a specific shape or design or to imply aspecific transponder type, but rather to indicate only that transponderscan be readily installed either during or after manufacture of a tire.More specifically, a transponder can be installed within a tire duringthe tire's manufacturing process or afterwards, and it need notspecifically be embedded within the tire's elastomeric matrix as shownin FIG. 6. The transponder is located on the radially inner side of thetire's radial ply and can be installed before or after the tire“shaping” process commonly used during its manufacture prior tolamination of the belt and tread materials. Advantageously, theconductive hoop in the tire can be added after the shaping process,which is desirable if it is substantially inextensible.

Furthermore, while the patch-type transponder devices 700,801 shown in

FIGS. 7A and 8B includes a slit 752 or hole 852 through which the airpressure in the tire can communicate with the internal transponder702,802 disposed beneath the patch cover 772, such a slit or otheropening is not necessarily required in order to sense and monitor atire's internal pressure or other parameters. For example, U.S. Pat. No.5,731,754, to Lee, Jr., et al. and entitled “Transponder and SensorApparatus for Sensing and Transmitting Vehicle Tire Parameter Data,”describes a pressure-sensing transponder system that is able to monitortire pressure and temperature data through an elastomeric membrane.

In the remainder of this disclosure, the numeral 801 or its equivalentwill be used to refer to a generalized passive transponder that isaffixed to a tire by means of a patch that is bonded to an insidesurface of a tire either during manufacture of the tire or aftermanufacture. The numeral 801 will be used to refer to the generalizedtransponder, including both the patch cover and the transponder beneaththe cover.

A goal of the present invention is of course to provide for 360-degreereadability of the transponder, i.e., from any location around thecircumference of the tire. Thus, whether a given transponder isinstalled during manufacture of the tire or afterwards, and whether ornot a given transponder is embedded within a tire's elastomeric matrix,one goal of the present invention is to provide an electromagneticlinkage between a transponder and a hoop-type or loop-type primarywinding which enables the 360-degree readability of a transponder by oneor more external-to-the-tire interrogator antennas, whether the latterare hand-held or mounted permanently or semipermanently upon a vehicle.

FIG. 9 is a cross-sectional view of an example of a patch-typetransponder 902 (compare 801) disposed upon the innerliner 906 of arunflat tire 900 having, as does the tire illustrated in FIG. 6, anembedded structural hoop 910 having the requisite electrical propertiesto serve as the primary winding of the above-described transformerlinkage between a tire-mounted, patch-type transponder device 902 and anexternal interrogator antenna (not shown). The patch-type transponder902 shown in FIG. 9 should be taken to represent either afactory-installed unit or an after-market unit. And while FIG. 9 shows apatch-type transponder 902 disposed outside of the equatorial plane EPof the tire, the transponder could as well lie directly on or somedistance to either side of the equatorial plane, the sole criterion ofimportance in the geometric relationship of the patch transponder 902and the reinforcing hoop 910 being the above-described electromagneticlinkage between the hoop 910, as a primary winding of a transformer, andthe transponder coil (not shown) of transponder 902, as the secondarywinding.

Referring to FIG. 9, the electrically conductive structural hoop 910,disposed between the carcass structure 960 and the belt structure 946,could be abbreviated into a non-structural wire, cable or flat ribbon orstrip of metal as shown in FIG. 10, where a ribbon 1010 of conductivematerial is shown disposed between the carcass structure 1060 and thebelt structure 1046 of a tire 1000 which is of the sidewall-reinforcedrunflat design. Those skilled in the art of tire construction shouldunderstand that the installation of such a ribbon-like electricallyconductive hoop/loop 1010 would obviously take place during that phaseof the tire-building process when the tread and breaker assembly isinstalled upon the green carcass that has been blown up into thecharacteristic toroidal shape of a tire. In other words, the ribbon-likeloop 1010 would be installed as part of the combination of tread and thebelt structure. The ribbon loop 1010 would coact with transponder 1002,preferably disposed on the inner side of carcass 1060.

FIG. 11A is a view of the central portion 1100 of the tire section 1000shown in FIG. 10, with a patch-type transponder 1102 bonded radiallyinward of the innerliner 1106 and near the electrically conductiveribbon-shaped hoop/loop 1110 disposed radially outward of the carcassstructure 1160 and radially inward of the belt structure 1046. The patchtransponder 1102, affixed to innerliner 1106, includes a cover 1150which is bonded to the innerliner 1106. While the patch transponder 1102is shown centered on the equatorial plane EP along with the hoop 1110,it is not necessary that either the transponder or the hoop be in thesame plane with one another nor that either be in or on the tire'sequatorial plane, but only that the hoop and the transponder be disposedin relation to one another in such a way that the hoop 1110 and the coilof the passive transponder 1102 are in electromagnetic communicationwith one another.

The illustrations that follow all use the same numerical designationsfor tire parts that are essentially similar.

FIG. 11B is a view of the central portion 1100 shown in FIG. 10, with anembedded transponder 1102 disposed radially inward of the electricallyconductive hoop 1110. While the embedded transponder 1102 is showncentered on the equatorial plane EP along with the loop or hoop 1110, itis not necessary that either the transponder or the hoop be in the sameplane with one another nor that either be on or in the tire's equatorialplane, but only that the hoop and the transponder be disposed inrelation to one another in such a way that the hoop 1110 and the coil ofthe embedded passive transponder 1102 be in electromagneticcommunication with one another.

If the transponder 1102 is intended to monitor and transmit tirepressure information, then clearly its pressure transducer (not shown)will have to be in communication with the inside of the tire. As hasbeen stated, there are prior art methods by which holes can be createdin the innerliner 1106 and the carcass ply 1160, and there also existpressure transducers that are able to monitor pressure within a tireeven though the transducer is separated from the inside of the tire by amembrane of gas-impermeable material.

FIG. 11C is similar to FIG. 11B except that the embedded transponder1102 is disposed radially outward the hoop 1110, and both the hoop andthe transponder are radially outward of the carcass structure 1160 andradially inward of the belt structure 1146. While the embeddedtransponder 1102 is shown centered on the equatorial plane EP along withthe loop or hoop 1110, it is not necessary that either the transponderor the hoop be in the same plane with one another nor that either be onor in the tire's equatorial plane, but only that the hoop and thetransponder be disposed in relation to one another in such a way thatthe hoop 1110 and the coil of the embedded passive transponder 1102 bein electromagnetic communication with one another. Clearly, thedisposition of the transponder 1102 in a location that is radiallyoutward of the hoop 1110 will present difficulties with respect to themonitoring of gas pressure within the pneumatic tire, but allowance fora communicating hole between the inside of the tire and the pressuretransducer associated with the transponder 1102 can be achieved by thevarious methods mentioned above for creating the necessary communicativechannels (not shown).

FIG. 11D shows yet another proposed location the hoop 1100, that iswithin the belt structure 1146, between the two or more belts 1162,1164of the belt structure 1146. No transponder is shown. A transponder mightbe installed as a patch-on type, during or after manufacture of thetire, or a transponder might be embedded in the tire near to the hoop1102 as shown in the previous FIGS. 11B and 11C. The hoop 1110 could beinstalled upon a green tire carcass at the same time that the tread andbelt structure are installed or as part of the tread/belt structurepackage. While the hoop 1110 is shown centered on the equatorial planeEP, it is not necessary that the hoop 1110 be in the equatorial planenor that any transponder (not shown) be centered upon the equatorialplane as long as the hoop and transponder be disposed in relation to oneanother in such a way that the hoop 1110 and the coil of the transponderbe able to achieve reliable electromagnetic communication with oneanother.

While the FIGS. 11A,11B,11C and 11D show the hoop 1110 in variouslocations with respect to the belt structure 1146, the preferred andmost practical location of the hoop/loop is radially outward of thecarcass structure 1160 which, during manufacture, as those skilled inthe art of tire building will know, must undergo an expansion from acylindrical shape to a toroidal shape prior to the installation of thetread and belts and the hoop. The transponder can be installed by anydesired means, such as the patch cover method as described above (seeFIG. 7A). Also, it is within the spirit and scope of the presentinvention that the loop or hoop need not be centered upon the equatorialplane of the tire. Furthermore, the hoop 1110 need not comprise a flat,ribbon-like homogeneous electrically conductive material. For example,FIG. 12 shows a patch-type transponder 1202 bonded to the radiallyinward side of the innerliner 1206 of a tire 1200 in which amulti-strand cable 1210 of electrically conductive material has beenwound about the radially outward perimeter of a blown-up green tirecarcass prior to installation upon the carcass of the tread and breakerassembly. The patch-type transponder 1202 could be installed eitherduring manufacture of the tire or afterward. FIG. 12 shows thepatch-type transponder 1202 and the cable hoop 1210 not centered on theequatorial plane EP, with the transponder additionally being outside theplane of the cable hoop 1210, thus indicating that a tire designerincorporating the present invention has some latitude in the design of atire-mounted transponder system employing the hoop primary transformerwinding as part of the system with which the transponder interacts withthe antenna of the transponder interrogator that is external to thetire. The hoop 1210 could as well be used in conjunction with atransponder that is embedded in the tire during manufacture of the tire.

FIG. 13 illustrates yet another hoop 1310 configuration in a radialmedium truck tire 1300 having a divided or split belt structure 1346comprising two laterally spaced apart belt sections 1346 a,1346 b andtwo belt sections 1346 c,1346 d that are disposed more or lesssymmetrically with respect to each other about the equatorial plane EP.Medium truck tire 1300 further has a tread 1338 and a carcass 1360. Aribbon-type hoop 1310 shown between the tread 1338 and the carcass 1360is disposed at a location between the divided belt sections 1346 a,1346b. A transponder 1302 can be incorporated as discussed above, forexample on the inner side of carcass 1360. While the hoop 1310 is shownto be of the flat, ribbon type, but it could also be made of solid metalhaving a circular cross section, or it could be a stranded or woundconductive cable as long as it satisfied the electrical criteria listedabove.

Second Embodiment

FIG. 14 shows, in meridional cross-sectional view, a runflat radialpneumatic tire 1400 having a tread 1438, two reinforced sidewalls 1464a,1464 b, two bead regions 1466 a,1466 b each containing an inextensiblebead 1468 a,1468 b, a carcass structure 1460 comprising two radial plies1470,1472 and a first pair of wedge insert reinforcements 1474 a,1474 bdisposed between the innerliner 1406 and the first ply 1470 and a secondpair of wedge insert reinforcements 1476 a,1476 b disposed between thefirst ply 1470 and the second ply 1472, a belt structure 1446 comprisinga first belt 1480 and a second belt 1482, and a ribbon-like,electrically conductive and electrically continuous single-turn hoop1410 disposed radially outward of the carcass structure 1460 andradially inward of the tread 1438 and the belt structure 1446. The hoop1410 serves the above described function of being an electromagneticcoupling element between a transponder 1402 that is either embedded,during manufacture of the tire 1400, within the elastomeric material ofthe tire or installed in the tire, such as in the radially inwardsurface of the carcass structure 1460, at some period after the tire hasbeen manufactured, as shown. The hoop has a single-turn electricalresistance that is preferably less than 10 ohms and is constructed ofmaterial resistant to fatigue and corrosion in the environment of aninterior of a pneumatic tire. The hoop might be more or less rectangularin cross section and be made of a solid band of electrically conductivematerial or made from a multiplicity of strands of electricallyconductive material.

The tire 1400 depicted in FIG. 14 is an exemplary embodiment of thepresent invention. The ribbon-like hoop/loop 1410 is not intended, asmentioned herein above, necessarily to have a rectangular cross section.The hoop 1410 could also be round in cross-section or have some othernon-rectangular cross section to be within the spirit and scope of thepresent invention. That is, the hoop 1410 could be made of a singleelectrically conductive element such as a metal wire or multiple braidedor stranded conductive elements that constitute a single electricallyconductive element. The belt structure 1446, which as shown in FIG. 14comprises two belts 1480,1482, could alternatively comprise more thantwo belts. Thus, while the hoop 1410 shown in FIG. 14 is shown disposedbetween the carcass structure 1460 and the belt structure 1446, it couldas well be disposed between any two of the two or more belts 1480,1482or radially outward of the belt structure and radially inward of thetread 1438 in order to satisfy its function as an electromagneticcoupling element. Also, while the electrically continuous single-turnhoop 1410 is shown in FIG. 14 to be more or less contiguous with theequatorial plane EP, the hoop could as well lie outside of theequatorial plane.

It is within the spirit and scope of the present invention that thelocation of the primary transformer hoop in any of the embodimentsdescribed above be located within any lateral location radially inwardof the tread region, including the lateral most shoulder portions of thetread region, and that the loop can be of any practical cross-sectionalshape, including for example but not limited to the like of a flatribbon, stranded metal cable or a single wire.

Regarding the various embodiments of the hoop/loop described herein, itshould be understood that the hoop is an exemplary complete, endless,short-circuit loop of any electrically-conductive material suitable tofunction as a coupling element. The hoop/loop is suitably brass-platedhigh-tensile strength steel which exhibits good mechanical strength andresistance to fatigue and corrosion when placed in the environment of aninterior of a pneumatic tire. The hoop may comprise multiple turns ofone or more metal filaments or cables, and these may be embedded in amatrix of conductive rubber. The hoop may comprise multiple strands ofsuch wire, which optionally may be plated, e.g., with nickel or gold ora chemically equivalent metallic material). The hoop should have a lowelectrical resistance, preferably less than 10 ohms. Furthermore, it iswithin the scope of the invention that the hoop element may be formed astwo or more lengths of wire joined at their ends in any suitable manner,such as by wrapping, welding or soldering, to form a complete hoopextending around the entire circumference of the tire.

Although the invention has been illustrated and described in detail inthe drawings and foregoing description, the same is to be considered asillustrative and not restrictive in character—it being understood thatonly preferred embodiments have been shown and described, and that allchanges and modifications that come within the spirit of the inventionare desired to be protected. Undoubtedly, many other “variations” on the“themes” set forth hereinabove will occur to one having ordinary skillin the art to which the present invention most nearly pertains, and suchvariations are intended to be within the scope of the invention, asdisclosed herein.

What is claimed:
 1. A pneumatic radial ply tire having a tread, acarcass structure, a belt structure, the tire characterized by: anelectrically conductive and electrically continuous single-turn hoopdisposed within or radially inward of the tread and belt structure andradially outward of the carcass structure; and a transponder coupledwith the hoop.
 2. The tire of claim 1 in which the transponder isdisposed on an opposite side of the carcass structure from the hoop. 3.The tire of claim 2 in which the electrically continuous single-turnhoop is on a radially outward side of the carcass structure and thetransponder is on a radially innerward side of the carcass structure. 4.The tire of claim 2 in which the electrically continuous single-turnhoop lies outside of the equatorial plane of the tire.
 5. The tire ofclaim 1 in which the electrically continuous single-turn hoop has anelectrical resistance about its circumference of preferably less than 10ohms.
 6. The tire of claim 1 in which the electrically continuoussingle-turn hoop is more or less contiguous with the equatorial plane ofthe tire.
 7. The tire of claim 1 in which the electrically continuoussingle-turn hoop is within the belt structure.
 8. The tire of claim 1 inwhich the electrically continuous single-turn hoop is disposed radiallyoutward of the belt structure and radially inward of the tread.
 9. Thetire of claim 1 including sidewalls reinforced with inserts for runflatcapability.
 10. A pneumatic radial truck tire having a tread, a carcassstructure, and a divided belt structure located between the tread andthe carcass structure, the divided belt structure having two laterallyspaced apart sections that are disposed more or less symmetrically withrespect to each other about the equatorial plane, the tire beingcharacterized by: an electrically conductive and electrically continuoussingle-turn hoop disposed radially inward of the tread, and between thetwo laterally spaced apart sections of the divided belt structure. 11.The tire of claim 10 in which the electrically continuous single-turnhoop has an electrical resistance about the circumference of the tire ofpreferably less than 10 ohms.
 12. The tire of claim 10 further includinga transponder disposed on the opposite side of the carcass structurefrom the hoop.